Estimating suspended sediment discharge and its annual mass balance in the Japanese first-class watersheds

Mayu Tateno, Yoshiyuki Yokoo, Chris Leong

Received 29 June, 2023
Accepted 24 September, 2023
Published online 8 December, 2023

Mayu Tateno1), Yoshiyuki Yokoo2), Chris Leong3)

1) Graduate School of Symbiotic Systems Science, Fukushima University, Japan
2) Faculty of Symbiotic Systems Science, Fukushima University, Japan
3) LINKAGE Project, Research Institute for Humanity and Nature, Japan

Toward comprehensive sediment management in Japan, the present study estimated suspended sediment discharge in the downstream areas of 109 first-class river watersheds based on the relationship between suspended sediment (SS) discharge L and water discharge Q as well as the volumetric changes of the watersheds. Firstly, we collected literature that reported LQ relationships and we identified LQ equations for the monitoring stations of all 109 first-class rivers. Secondly, we calculated annual average SS discharge rate L for all stations using the LQ equations. Finally, we calculated the annual average vertical movement rate and volume change. As a result, we found that: (1) SS discharge was high in eastern Hokkaido, northern Kanto, Chubu, Shikoku regions and parts of Chugoku region, (2) average vertical movement rates were high in areas around 40° north and in the central parts of Japan, (3) the volume increase was greater in Hokkaido, areas around 40° north and central parts of Japan, (4) net increases were greater in western Hokkaido, areas around 40° north, and in Kinki region, and (5) volume increase rates were high in areas around 40° north. There were also large volume decreases in the Shinano River watershed.

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Copyright (c) 2023 The Author(s) CC-BY 4.0

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